org.apache.paimon.mergetree.compact

Class ReducerMergeFunctionWrapper

java.lang.Object

org.apache.paimon.mergetree.compact.ReducerMergeFunctionWrapper

All Implemented Interfaces:

MergeFunctionWrapper<KeyValue>

public class ReducerMergeFunctionWrapper
extends Object
implements MergeFunctionWrapper<KeyValue>

Wrapper for MergeFunctions which works like a reducer.

A reducer is a type of function. If there is only one input the result is equal to that input; Otherwise the result is calculated by merging all the inputs in some way.

This wrapper optimize the wrapped MergeFunction. If there is only one input, the input will be stored and the inner merge function will not be called, thus saving some computing time.

Constructor Summary

Constructors

Constructor and Description
ReducerMergeFunctionWrapper(MergeFunction<KeyValue> mergeFunction)

Method Summary

Modifier and Type	Method and Description
void	add(KeyValue kv) Adds the given KeyValue to the MergeFunction helper.
KeyValue	getResult() Get current value of the MergeFunction helper.
void	reset() Resets the MergeFunction helper to its default state.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ReducerMergeFunctionWrapper

public ReducerMergeFunctionWrapper(MergeFunction<KeyValue> mergeFunction)

Method Detail

reset

public void reset()

Resets the MergeFunction helper to its default state.

Specified by:

reset in interface MergeFunctionWrapper<KeyValue>

add

public void add(KeyValue kv)

Adds the given KeyValue to the MergeFunction helper.

Specified by:

add in interface MergeFunctionWrapper<KeyValue>

getResult

public KeyValue getResult()

Get current value of the MergeFunction helper.

Specified by:

getResult in interface MergeFunctionWrapper<KeyValue>